Packaged photographic developing powder



Patented Aug. 17, 1954 PACKAGED PHOTOGRAPHIC DEVELOPING POWDER George Schwarz, Glen Head, N. Y., assignor to Powers Chemco, 1110., Glen Cove, N. Y., a corporation of New York No Drawing. Application October 22, 1952, Serial No. 316,315

4 Claims.

The present invention relates to a novel and improved photographic developer which can be packaged dry as a powder and is suitable for storage over long periods of time.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the steps, processes and compositions pointed out in the appended claims.

The invention consists in the novel steps, processes and compositions and improvements herein shown and described.

The present invention has for its object the provision of a novel and improved package of photographic developing powder which has improved keeping qualities even under conditions of excessive humidity andwhich avoids contaminat tion of the developer with rust from the metallic package in which the developer is packaged. A further object is the provision of a developer powder which is adapted to absorb even relatively large quantities of moisture without having deleterious, effects either on the developer itself or on the lacquered iron or tin-coated con" tainer in which the developer is packaged for shipment and storage.

'Various suggestions have been made to improve dry packages of developers. The developing substance such as hydroquinone, pyrogallol, monomethyl paraminophenol (metol) and other organic developing agents are easily oxidized in storage, particularly in the presence of humidity, the slightest degree of oxidation showing up as discoloration. Simultaneously the metal container itself is often oxidized, resulting in disadvantageous rust. Even dry chemical mixtures in a lacquer coated steel can show undesired oxidation symptoms when packaged under normal conditions of humidity.

I have found that dry mixtures of developers can be considerably better preserved against moisture, oxidation and interaction with the metal can by incorporating delta-gluconolactone into the developer-powder mixture. Such mixtures are much less susceptible to oxidation and discoloration than similar mixtures without the addition of the lactone.

According to the present invention there is added to the dry developing powdercomprising the organic developing agent and as some of the salts to be incorporated in the developing solution a small proportion of delta-glucono-laotone which acts to preferentially absorb any moisture which is within the package, thereby dehydrating the organic developingagent and the developer salt and consequently preventing oxidation of the developing agent and the metal of which the container is made. As the delta-glucono-lactone all 2 is acted on by the moisture, it is converted into gluconic acid which acts asa moisture sequestering agent, and continues the effect even if rel atively large quantities of moisture come in contact with the developer powder. The deita-glucono-lactone, as well asthe resulting gluconic acid, have no effect on the action of the developer except such effect as can be overcome by the addition of an equivalent amount of alkali to maintain the alkalinity of the developer at the desired value.

In general, the developer is formulated in accordance with the desired formula, an additional quantity of alkaline material, such as sodium carbonate, borax or other alkali-producing powder is added, the amount being equivalent to the amount of delta-glucono-lactone to be added, and then delta-glucono-lactone is added in an amount from 1 to 30% and more preferably from 2 to 10 of the amount of the dry ingredient to be included in the package. The orderof mixing of the various dry ingredients is immaterial, and the deltaglucono-lactone may be added to any of the organic developing powder mixtures, whether these are packaged in several separate containers which are to be to form a single developing solution, or whether all of the ingredients for a single developer are included and mixed in a single package. However, delta-glucono-lactone is preferably used with developers which are packaged in two or more separate containers which are later to be mixed, and in such a case there is preferably included in that portion which includes the organic developing agent as a powder mixed with other ingredients such as sodium sulfite, sodium formaldehyde bisulfite, potassium metabisulfite or the like and preferably, without the addition of alkaline materials such as the alkaline carbonates and borates.

It will be understood that the foregoing general description and the following detailed desoription as well are exemplary and explanatory of the invention butare not restrictive thereof.

The following examples will serve to further illustrate the compositions of the present invention:

EXAMPLE 1 A powder developer is prepared to be packaged in ordinary tinned-steel containers in sufficient quantities to form a liter of developing solution. Such a powder developer composition preferably comprises two parts, as follows:

Part A Grams Sodium sulfite, desiccated .a 45.0 Hydroquinone 16.0 Potassium bromide 1.9

Delta-glucono-lactone 6.0

2,686,? 18 3 4 Part B EXAMPLE 7 Sodium arbonate desiccat d g; In case the developer contains metol as one of e the developing agents, it is preferable that the EXAMPLE 2 metol be packaged separately from the sulfite so The following ingredients, mixed, may be packaged in similar cans to provide sufficient developer ingredients to make 1000 cc. of developer.

The developing agent of a two solution developer, in which the alkali is packaged separately from the organic developing agent, may be compounded as follows: I

I Grams Pyrogallic acid 1 18.3 Sodium sulfite, desiccated 74.0 Potassium metabisulfite 17.3 Delta glucono-lactone 20.0 Potassium bromide .z 4.6

These ingredients are to be dissolved in, a liter of water mixed with the solution of alkali from the other part of the developer, and then diluted for use. 7 2

' EXAMPLE 4 Another developer, made up in two packages, one to contain the alkali, and the other the developing agent and preservative, may have the developing agent compounded as follows:

Grams Hydroquinone 60 Sodium formaldehyde bisulfite' 180 Delta-glucono-lactone 15 For use, this is tobe dissolved in water and mixed with the requisite quantity of alkali from the accompanying package.

EXAMPLE 5 .A dry mixture is made of Y r I v Grams I-Iydroquinone :32 Sodium bisulfite 32 Potassium bromide 8 Delta-glucono-lactone 1.5

which is to be dissolved in llitre of water for use and then mixed with an equal quantity of a solution of 60 grams of sodium hydroxide in one litre of water, preparing it for use;

EXAMPLE 6 A dry mixture of a developer which does not require any alkaline agent may be compounded as follows: 1 V i Grams Diamidophenol W Sodium sulfite, anhydrous 20 Potassium bromide 0.2 Delta-glucono-lactone 1.5

This provides suflicient developer to make 1000 cc. of developing solution. v

that the metal is more readily soluble, and in such a case the delta-glucono-lactone is preferably added to the organic developing agent or agents, while the sulfite and alkaline agents are mixed and separately packaged. For such a developer the two following dry mixtures are separately packaged:

Part A Grams Metol l0 Hydroquinone 10 Delta-glucono-lactone A 3 Part B Sodium sulfite, anhydrous 100 Sodium carbonate, anhydrous 60 Potassium bromide 1 In order to test the effectiveness of the preservative action of delta-glucono-lactone tests have been made of the keeping qualities of dry developers in accordance with the present invention by making up batches of dry developing powders of similar composition, except that one of each pair of similar batches omitted the deltaglucono-lactone. These batches were concurrently prepared under similar conditions of temperature and relative humidity from the same lots of raw materials and then packaged in identical metal containers. 7 After one month of storage, the samples omitting the delta-gluconolactone showed distinct coloration, while the sampies including the delta-glucono-lactone did not discolor during the testing period of six months.

The invention in itsbroader aspects is not lim-. ited to the specific steps, processes and compositions shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages What is claimed is:

1. A stabilized packaged developer powder comprising a dry powdered mixture of developing agents including an organic silver halide developing agent and from 1 to 30% of delta-glu cono-lactone. I 7 t 2. A stabilized packaged developer powder comprising a dry powdered mixture of developing agents iucludingan organic silver halide developing agent and from 2 to 10% of deltaglucono-lactone. I

3. A stabilized packaged developer powder comprising a dry powdered mixture of developing agents including a soluble sulfite, an organic silver halide developing agent and from 1 to 30% of delta-glucono-lactone,

4. A stabilized packaged developer powder comprising a dry powdered mixture of develop-v ing agents including a soluble sulfite, an organic silver halide developing agent and from 2 to 10% of delta-glucono-lactone,

References Cited in the file of this patent UNITED STATES PATENTS 7 Number Name I Date 2,257,440 Wood 'Sept.30,1941 

1. A STABILIZED PACKAGED DEVELOPER POWDER COMPRISING A DRY POWDERED MIXTURE OF DEVELOPING AGENTS INCLUDING AN ORGANIC SILVER HALIDE DEVELOPING AGENT AND FROM 1 TO 30% OF DELTA-GLUCONO-LACTONE. 